Commutator construction for dynamo-electric machines.



T. S. ALLEN.

GOMMUTATOR CONSTRUCTION FOR DYNAMO ELECTRIC MACHINES.

APPLICATION/FILED FEB.2B, 1910.

1,017,945. Patented Feb. 20, 1912.

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lV- VYIWQIQ 3 Q0 g7) xiyu X O 3 1 44: a. Giz I 0W0 mow UNITED STATES P JENT OFFICE.

mom 8. ALLEN, OF MIIiWAUKEE, WISCONSIN, ASSIGNOB TO ALLIS-CHALMEBS COMPANY, A. CORPORATION OF NEW JERSEY.

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Specification of Letters Patent.

Patented Feb. 20, 1912.

Application filed February 28, 1910. Serial No. 546,541.

To all whom it may concern: a

Be it known that I, Tnoms S. ALLEN, a citizen ofthe United States, residin at M11- waukee, in the county .of Milwau cc and State of Wisconsin, have invented certain new and useful Im rovements in Commutator Constructions or Dynamo-Electric Machines, of which the following is a full, clear, and exact specification.

This invention relates to dynamo-electnc machines,-and particularly to improvements in construction and means for cooling commutators of high speed "machines, such .as turbo generators. a

It is a wellknown fact that the commutators of machines of high speed and of 1 ar e current output must .be made relatlve y small in diameter, and even thou h the commutator is given considerable I on h the segments become hot due to the big brush friction, and contact losses. In such machines 'considerable difiiculty has .been experienced in sup tingthe segments, a'rticularly when t e segments are long, in a manner such that they will not buckle or. be

distorted and shifted from position by ex-- pansion or b centrifugal force, and ithas also been difiibult to cool thecommutator n a satisfactory manner and prevent a rise in temperature which would affect the efiiciency and operation of the commutator and brushes.

The object of the invention is to lmprove the ventilation of commutators and-to secure a better coolin effect than has been possible heretofore, an to support the segments in a manner such that there is no danger of the segments being displaced and so'that a good circulation of air can take place through the interior of the commutator and along the entire inner surfaces of the segments.

In carrying out my invention I provide as ent clamping and supportinfg means wfii h engages the outer surfaces 0 the segments only, so that the entire inner surface of each'segment is exposed to air currents which may be forced through the interior of the commutator. 'This is preferably accomplished by means of clamping rings which are arranged, tightly about the segments and which hold them securely in assembled relation in the form of an annulus or shell, the inward displacement of the segments bein of course, lmpossible because of the tapered or wedge shaped construction of a of the segments. The annulus is preferably sup orte concentrically with respect to the sha t of the machine by su porting devices which extend between the s aft and two of the clamping rings near the ends of the segments, these supportin devices being preferably in the form of dlSkS which are mounted upon the shaft, and are provided with openmgs through which air may pass freely to and from the commutator. Air may be caused to circulate or pass through the commutator by any suitable fan or blower, which, according to the present invention is mounted on the shaft near the outer end of the commutator.

The invention may be'further briefly summarized as consistin in certain novel details of' construction an combinations and arranglements of partswhich will be described 1n t e specification and set forth in the appended claims.

Reference is had to the accompanying sheet of drawings, in which- Figure 1 is a partial elevation and partial longitudinal sectional View of part of an armature of a dynamo-electric machine and of a commutator constructed in' accordance with my invention Fig. 2 is a sectional view A substantially along the line 2-2 of .Fig. 1 looking in the'direction indicated by the arrow, part of the blading of the fan or blower being removed; Fig. 3 is .a plan view portion of one of the split segmentclamplng rings; and Fig. 4 is an enlarged sectional view through a portion of the blading of the blower. I

Referring now to the figures of the drawings, 10 represents a portion of the armature, and 11 the shaft of a direct current dynamo-electric machine such as a turbogenerator or other direct current machine having a long commutator the segments of which are shown at 12.

Instead of clamping the segments onto seats or inner supporting devices, or of employing V-shaped clamping rings engaging undercut slots in the ends or inner surfaces of the segments, as is the present common practice, I leave the segments unsupported on the interior and hold them in assembled relation or in the form of an annulus or' shell by clamping devices which surround the segments and engage the latter on the exterior only. In this case this is accomplished by means of several sets of clamping rings each set consisting of an inner tapered and adjustable ring 13 having its outer surface threaded and an outer ring 14 which is ta ered and threaded on its inner surface an is screwed tightly upon the inner ring 13 so as to contract the inner ring and draw the segments tightly together. Eachof the inner rings 13 1s rendered adjustable b being split or by means of a dia onal s 0t 15 shown most clearly in Fig.

3. hree sets of rings are here shown, two

correspondingly tapered portions of the segments. This construction assures against endwise shifting of the segments relative to the clamping rings. It will be seen that the segments and rings form a unit and may be easily assembled remote from the machine and afterward secured on the shaft, or removed as a whole from the machine. The annulus or shell of segments is supported concentrically with respect to the shaft, and in a manner such as to leave an annular space between theinner surfaces of the segments and the shaft, by means of two disks 17 which are mounted on the shaft and are secured by screws 18 to horizontally projecting annular flanges 19 on the outer clamping rings 14 of the sets of rings at the ends of the commutator. The disks may be keyed to the shaft and are held in proper position axially thereof by a shoulder 20 which is engaged by the inner disk 17 adj'acent'thearmature, and by nuts 21 which engage a threaded portion 22 of the shaft and bear against the outer disk 17. Each of the disks 1'? is provided with a number of ventilating openings 23 which permit free circulation of air through the interior of the commutator. 1

vAny suitable fan or blower may be utilized for forcing air through the interior of the commutator, but in this case, the blower is mounted on the shaft adjacent the outer end of the commutator and includes a series of inclined curved blades 24 which are quite similar to the blades of a turbine. These blades have bases which are secured by a calking strip 25 in the slot of a base ring 26 which is keyed to the shaft, and have their outer ends secured to a shroud ring 27. The blades are surrounded by a cylindrical casing 28 which is secured to the face of the adjacent commutator supporting disk 17. It will be seen. that with the segment clamping and supporting means which I have provided, the segments will be clamped 65 and held securely in position against displacement and at the same time an unobstructed annular passageway is formed be.- tween the shaft and the inner surfaces of the segments. When the machine is in operation a large volume of air is forced through the interior of the commutator sweeping along the entire inner surfaces of the segments in a manner such as to cool them most effectively. The direction of rotation of the machine is indicated by the ion arrow in 76 Fig. 4, and the direction in whic the air is forced by the blades is indicated by the shorter arrows in Fig. 4 and by the arrows in Fig. 1. With this construction the commutator-can be cooledvery efi'ectively,the 30 life of the se cuts and brushes is rendered greater than 1n the machines at present employed, and the operation of the'commutator-and brushes will be satisfactory at all times providing brushes of suitable capacity 35 are employed.

I do not desire to be confined to the exact details shown, but aim in my claims to cover all modifications which do not involve a departure from the'spirit and scope ofmy invention. v I

What I claim as-new and desire to secure by Letters Patent is 1. In a commutator construction, a shaft,

a plurality of segments surrounding said shaft, segment clamping and supporting means engaging the outer surfaces of the segments only and means carried by the shaft for creating a flow of air between said segments and shaft.

2. In combination, a shaft, a-commutator comprising segments in the form of an annulus, the segments'being clamped together and held in assembled relation on the exterior only, means for supporting the annulus concentrically with respect to the shaft so as to leave an unobstructed air space between the inner surface of each segment and the shaft, and means on said shaft for forcing air through the interior of the commutator.

3. In a dynamo-electric machine, a shaft,

a commutator comprising a plurality of segments arranged in the form of an annulus or shell, said segments being clampedtogether and held in assembled relation from the exterior only, and being supported from the shaft so as to leave an unobstructed annular passageway between the segments and the shaft, and means mounted on said shaft for creating a flow of air through said annular passagewa 4. In combination, in a dynamo-electric machine, a shaft, a commutator comprisingv an annulus or shell of segments, clamping rings engaging the outer surfaces of the segments and holding the latter in assembled relation, means mounted on the shaft for holding the annulus of assembled se ents concentrically with respect to the sha so as to' leave an unobstructed passageway be- 130 tween the segments and the shaft, and means for causing a circulation of air through said passageway.

5. In combination, in a dynamo-electric machine, a shaft, a commutator comprising an annulus or shell of commutator segments, clamping rings engaging the outer surfaces of the segments only and holding the latter in assembled relation, means extending between said rings and shaft and beyond the ends of the segments for holding the annulus concentrically with respect to the shaft so as to leave unobstructed space between the shaft and the segments, and a blower for forcing air through said passageway along the inner surfaces of the segments throughout their length.

6. In combination, in a dynamo-electric machine, a shaft, a commutator comprising an annulus or shell of segments, clamping rings extending about the commutator for holding the segment-s in assembled relation, said segments being supported from the shafts so as to leave an unobstructed annular passageway between the segments and the shaft, and a blower mounted on the shaft for forcing air through said passageway, said blower comprising blades secured to a plurality of rings. a

7. In combination, in a dynamo-electric machine, a shaft, a commutator supported concentrically relative to said shaft so as to leave an unobstructed passageway between said shaft and commutator, a blower mounted on said shaft at one end of said commutator for forcing air through said passageway, said blower comprising blades secured to rings at their extremities, and a casing surrounding said blades for directing the forced air.

Milwaukee, Wisconsin, February 16, 1910.

In testimony whereof I afiix my signature, in the presence of two witnesses.

THOMAS S ALLEN.

Witnesses CHAS. L. BYRON, Ron. E. STALL. 

